The following answers for the Causes and Consequences features are examples and are not intended to represent a comprehensive list. In addition, the sequence of items is not meant to connote relative importance Sort the examples below into the appropriate bin. Think about which factors contribute to the spread of invasive species (causes), the consequences that result from the spread of invasive species, and possible solutions. Reset Help economic costs for control and removal of invasives decline of native organisms due to competition with invasives improved manual or chemical control measures increased global transport and mobility favorable conditions for invasives due to climate change stricter policies aimed at ballast water dumping and other particulars change in community structure and function Causes Consequences Solutions

Dispersion refers to the change in an organism's range or distribution area. Different ecological and biogeographical processes might be involved in organisms' dispersion. The term "jump dispersion" refers to a few individuals in a short time that can cross a barrier and occupy a new area. In this situation, the establishment is not always for sure. For this to happen, they must reproduce and start a new population of a certain size that can survive the new conditions.

Biologic Invasions refer to new species that establish in a new area far or out of their original distribution range. Once established, these species might be considered exotic or invasive, according to their reproductive rate, population growth, and interaction with native species.

The exotic species is the one that has been introduced and got to establish, but causes no damage or alteration to native ecosystems.

The invasive species is introduced into a new area, establishes, expands its distribution from the first invaded spot, and overgrows. As they expand, they compete with other native species for resources such as water, place, radiation, exposure, shelter, source of food, among others. Species are considered to be invasive because of their reproductive rate, population growth, and interaction with native species, which provokes huge damages to the native ecosystem.

It is very common for these species to escape and start new populations in the new area, where they have less environmental pressure and better conditions than in their origin area -fewer predators, more resources, better nitches-, and these factors favor their establishment.

There are some typical steps in an invasion process:

1) Introduction or dispersion to the new area,

2) Naturalization. The new species establishes in the new area. It can grow, reproduce and make use of resources.

3) Overgrowth and uncontrolled expansion.

4) Interaction with other species.

5) Stabilization.

Biologic invasions are natural processes, that occur in small groups of individuals that can expand to other ecosystems. Their expansion is promoted by the appearance or disappearance of barriers. But these biological invasions have been accelerated by human beings, referring to this as human-assisted invasions. These are the cases in which men transport species from one place to the other for different uses or purposes.

Once a species has become invasive, it turns very hard to eliminate it, especially because it requires big mechanical and economical effort. However, they can be controlled to avoid their wider expansion. There are different ways of controlling invasive species

Mechanical
Chemical
Biological